Sealed vs. Ported vs. Passive Radiator - AVS Forum
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post #1 of 24 Old 02-09-2011, 11:41 PM - Thread Starter
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Ok, so I know all of the general differences between sealed and ported (sealed is cleaner/better for music, ported generally gives more output, extends lower, but is boomy/better for HT, etc.).

However, where does passive radiator fit into the mix? I know technically its considered sealed, but does it have the same characteristics, or is it somewhere in between sealed and ported?

I'm wondering because my tastes lead me to believe that I'm more suited for ported. However, the best sub I've ever owned is my Klipsch RSW-12 (passive radiator design). I also have a Klipsch RW-12D (ported), a Velodyne VX-11 (10" ported and yes, I know its cheap), and I've owned a Velodyne DLS-5000R (15" ported). So, is the passive radiator design the best compromise between clean controlled bass, and low extending/high output? BTW, I'm aware they're typically more costly.

Thanks
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post #2 of 24 Old 02-09-2011, 11:56 PM
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If you just scroll down a bit on this post over at another forum, you can read all about the various subwoofer designs and their benefits/shortcomings.

http://forum.blu-ray.com/subwoofers/...justments.html
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post #3 of 24 Old 02-10-2011, 03:40 AM
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Actually, passive radiator designs are considered to be be ported alignments.

That "Big Daddy" link is an awesome resource for newbies.

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post #4 of 24 Old 02-10-2011, 10:04 PM - Thread Starter
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Quote:
Originally Posted by Maskclone2k View Post

If you just scroll down a bit on this post over at another forum, you can read all about the various subwoofer designs and their benefits/shortcomings.

http://forum.blu-ray.com/subwoofers/...justments.html

Thanks! Great link (added to faves). The link compares the passive radiator design to ported, but does not compare it to sealed. Based on the info, my guess is that the passive radiator design does sort of fall between sealed and ported characteristics.
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post #5 of 24 Old 02-11-2011, 05:52 AM
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From another sealed vs ported discussion

The design choice depends on $$$/driver/footprint and power available.

The important differences are .

1. Ported designs need less power to produce output down to their tuning point.
2. Ported designs have better output at their tuning frequency then sealed design when driver/amp are similar.
3. Sealed designs have more output below and above the tuning of a ported design.
4. Sealed designs can inherently protect the driver from over excursion if the box is small enough. Ported designs need a SubSonicFilter to protect the driver.
5. Sealed designs need far greater power to achieve high SPL down low because there is a HUGE boost down low to get output.
6. Audiophile myths like tighter bass are not worthy of any science discussion. Of course a port introduces more noise into the design.



The difference between ported and Passive Radiator is pretty simple.

1. PR allows for a smaller box with same tuning point.
2. PR offers less noise (NO port chuffing, etc).
3. PR costs a little more $$$ vs ported
4. Ported box will have a little higher max SPL vs same amp/driver in a PR design.

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post #6 of 24 Old 02-11-2011, 06:13 AM
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Quote:
Originally Posted by penngray View Post

3. Sealed designs have more output below and above the tuning of a ported design.

The sealed sub if unfiltered will extend deeper, but why do you say that it will have more output above the tuning? Given equal amounts of power, output above tuning should be similar. In fact within a good 1/2 octave or so above tuning, the output of the ported sub should be higher due to the port contribution which is not limited to only the tuning point, but covers a bit of a range.
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post #7 of 24 Old 02-11-2011, 06:24 AM
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Quote:
Originally Posted by mojomike View Post

The sealed sub if unfiltered will extend deeper, but why do you say that it will have more output above the tuning? Given equal amounts of power, output above tuning should be similar. In fact within a good 1/2 octave or so above tuning, the output of the ported sub should be higher due to the port contribution which is not limited to only the tuning point, but covers a bit of a range.

That is naturally how the output curves work in any model we do. Sealed designs have a different (rising) curve then a ported design. You have to model all these to understand what Im posting.

you also can not really say "equal amounts of power". Of course the ported sub will have more output with equal power because that is inherent to its design. If people want cheap output they build/buy a large ported design bcause it does not need a lot of power like a smaller sealed design.

EDIT:
I should clarify the "above tuning"...Its usually an octave above where the sealed design output is greater so Mike, yes at a 1/2 octive you are right about the ported having more output.

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post #8 of 24 Old 02-11-2011, 07:00 AM
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Quote:
Originally Posted by penngray View Post

That is naturally how the output curves work in any model we do. Sealed designs have a different (rising) curve then a ported design. You have to model all these to understand what Im posting.

you also can not really say "equal amounts of power". Of course the ported sub will have more output with equal power because that is inherent to its design. If people want cheap output they build/buy a large ported design bcause it does not need a lot of power like a smaller sealed design.

EDIT:
I should clarify the "above tuning"...Its usually an octave above where the sealed design output is greater so Mike, yes at a 1/2 octive you are right about the ported having more output.

Output of any particular sub design is going to be a product of it's sensitivity across the various frequencies in it's useable bandwidth x it's amplifier power, limited by it's power handling. The sub's sensitivity is typiclly referenced to it's output with 1 watt of power at some specified distance. If you eliminate the constant of "equal amounts of power," this becomes meaningless.
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post #9 of 24 Old 02-11-2011, 07:12 AM
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We are trying to point out the differences in designs not driver/power choices.

The constant of equal power is not the discussion. Did someone ask what one driver + 500watts do in a ported, sealed or PR design? Of course you can obtain that answer from my points. It would be pointless to compare a 500W Sealed design vs a 500W ported design (using the same driver).

The OP wants to know why he perfers ported subs and that is easy, he has never had a sealed design with enough power for the difference to matter. Sealed subs require more power down low to obtain output then a ported sub. Conclusion, Its pointless to build a sealed design and give it the same power as a ported design would have. Sealed designs cost more $$$ to get the same performance.

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post #10 of 24 Old 02-11-2011, 07:36 AM
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There is also an article on the differences in subwoofer design in the Velolounge section of our website.

When in comes to audio there are seldom right and wrong answers.  The opinions of "experts" are just that, and should be used as a suggestion only.  Remember at the end of the day it is your money, your system, and you will need to listen to it.
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post #11 of 24 Old 02-11-2011, 10:20 AM - Thread Starter
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Thank you all for the useful information. As Penngray suggested, I'm pretty sure that I would prefer a sealed sub, given I owned one with a significant amount of power. The velolounge information was very helpful in explaining where passive radiator fits into the equation. I appreciate the increased accuracy of PR over ported.
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post #12 of 24 Old 02-11-2011, 12:09 PM
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Code:
    [Bass Reflex]
         |
        / \\
 [ports]  [radiators]

data-bass.com
@databass_audio
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post #13 of 24 Old 02-12-2011, 08:11 AM
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I have a similar delimma. I currently have the Klipsch RW-12d sub in a 2,200 cubit foot HT. I'm thinking of upgrading sub and have one of each design in mind:

Ported - SVS PB13-Ultra
Sealed - SVS SB13-Plus
Passive Radiator - Definitive Technology Super Cube I


Given the size of my room and my love of tight, clean, musical bass - I am leaning toward sealed or passive radiator design.
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post #14 of 24 Old 02-12-2011, 08:32 AM
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If you're going the PR route and not in a huge hurry consider the PR kits from AE.

I have two of the P1512 kits (along with an EPIK Empire, also a good choice BTW) in a ~4000 cu ft room.

Sound quality is excellent and they are good ht performers as well.

They have had issues with driver production last year so check on that first.

http://www.aespeakers.com/phpbb2/vie...php?f=3&t=2441
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post #15 of 24 Old 02-28-2011, 11:37 AM
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Hey guys,

I recently upgraded my Energy esw-8 ported sub with a Velodyne Impact 10 ported sub. The main reason was because I got terrible port noise on many blu-ray movies with heavy LFE. However, even after upgrading I still get some port noise on the Velodyne. Velodyne also has an Impact-Mini which has a passive radiator. Do you guys think I would be better off with that unit, especially to eliminate port noise?

Thanks.
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post #16 of 24 Old 02-28-2011, 11:44 AM
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If you want to do just to movies with heavy LFE, you need a bigger sub, period. There is way more to it than just eliminating port noise. You need to move some serious amount oif air. Do not expect serious bass from an 18lb sub with a 6.5" driver. It's not going to happen.

Do yourself a favor and step up in size.
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post #17 of 24 Old 02-28-2011, 12:07 PM
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Quote:
Originally Posted by mojomike View Post

If you want to do just to movies with heavy LFE, you need a bigger sub, period. There is way more to it than just eliminating port noise. You need to move some serious amount oif air. Do not expect serious bass from an 18lb sub with a 6.5" driver. It's not going to happen.

Do yourself a favor and step up in size.

Thanks mojo. That's pretty much what everyone keeps telling me. I was trying to avoid going too big because I am limited for space. Would a decent 12" ported sub be enough you think?
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post #18 of 24 Old 02-28-2011, 12:40 PM
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12" subs is where things start getting serious. A decent 12" sub can do a great job in a smallish room. Then it gets down to a matter of budget.
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post #19 of 24 Old 02-28-2011, 12:41 PM
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Quote:
Originally Posted by savior sound View Post

I have a similar delimma. I currently have the Klipsch RW-12d sub in a 2,200 cubit foot HT. I'm thinking of upgrading sub and have one of each design in mind:

Ported - SVS PB13-Ultra
Sealed - SVS SB13-Plus
Passive Radiator - Definitive Technology Super Cube I


Given the size of my room and my love of tight, clean, musical bass - I am leaning toward sealed or passive radiator design.

I have tested the SCI against the SVS PB13 Ultra and the SVS blew away the SCI on every level. Heck I tested my two SC1's against my lower end SVS PB12 NSD/2 and the SVS blew away my dual SCI's witth cleaner and deeper output.
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post #20 of 24 Old 02-28-2011, 02:36 PM - Thread Starter
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Quote:
Originally Posted by savior sound View Post

I have a similar delimma. I currently have the Klipsch RW-12d sub in a 2,200 cubit foot HT. I'm thinking of upgrading sub and have one of each design in mind:

Ported - SVS PB13-Ultra
Sealed - SVS SB13-Plus
Passive Radiator - Definitive Technology Super Cube I


Given the size of my room and my love of tight, clean, musical bass - I am leaning toward sealed or passive radiator design.

That's funny because the sub I want to upgrade is the RW-12d also. I am happy with my RSW-12, but I don't want to spend near that kind of money again for my secondary HT set up. I got the RW-12d from Newegg for $350 and it is great for the money. I don't know if I can find anything else for near$350 range that I will be happy with.
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post #21 of 24 Old 02-28-2011, 02:47 PM
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Quote:
Originally Posted by mojomike View Post

The sealed sub if unfiltered will extend deeper, but why do you say that it will have more output above the tuning? Given equal amounts of power, output above tuning should be similar. In fact within a good 1/2 octave or so above tuning, the output of the ported sub should be higher due to the port contribution which is not limited to only the tuning point, but covers a bit of a range.


This is very true. The port contributes much more than what people think it does.

Cacimar Hernandez
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post #22 of 24 Old 11-11-2013, 09:21 AM
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I have owned all three subwoofer designs and I have really loved all of them. Suffice it to say, not all vented will sound the same. Ditto sealed and passive radiator. Subs are speakers, after all, and must be evaluated individually. There are great and horrendous examples of all three design principals.

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post #23 of 24 Old 11-11-2013, 07:30 PM
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Quote:
Originally Posted by thegoodguy View Post

...I'm pretty sure that I would prefer a sealed sub...I appreciate the increased accuracy of PR over ported.
PR is not automatically more accurate than ported. There are just different tradeoffs. The PR may not have port noise or port resonance, but brings its own nonlinearities into the picture. It *might* have less output than a really good port.

And I agree with the other poster-your problem of port noise is NOT one of sealed vs. ported etc. Your problem is you need stronger subwoofers. Sound pressure is generated by moving air, and high bass SPL requires moving a LOT of air. 8" and 10" cones just can't do that much unless the room is tiny (like a car) or you are using some kind of tapped horn or such. You can also Google "Hoffman's Iron Law" to see why high SPL doesn't happen out of tiny subwoofers, excepting a few with humongous amplifiers. Sunfire, for example. Those designs then usually ignite debates as to whether they sound amazing or horrible, as their small cones have to move a LOT which can generate other distortions.
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post #24 of 24 Old 11-11-2013, 08:03 PM
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I used to have a Sunfire True Subwoofer (high excursion 10" driver). I can attest that it sounded horribad.

It's pretty amazing how much noise a little box can make if you don't mind that most of it is distortion.
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